This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 1 | 9 |
| 2 | 81 |
| 3 | 225 |
| 4 | 841 |
| 5 | 2304 |
| 6 | 6084 |
| 7 | 18496 |
| 8 | 53824 |
| 9 | 150544 |
| 10 | 435600 |
| 11 | 1263376 |
| 12 | 3610000 |
| 13 | 10368400 |
| 14 | 29899024 |
| 15 | 85895824 |
| 16 | 246741264 |
| 17 | 709902736 |
| 18 | 2041232400 |
| 19 | 5866947216 |
| 20 | 16869853456 |
| 21 | 48507419536 |
| 22 | 139454446096 |
| 23 | 400947305616 |
| 24 | 1152814510864 |